CONSOLIDATED STATEMENTS OF CHANGES IN CAPITAL OF ERP OPERATING LIMITED PARTNERSHIP (Unaudited) - USD ($) $ in Thousands	Total	ERPOP [Member]	PREFERRED SHARES ERPOP [Member]	General Partner [Member] ERPOP [Member]	Limited Partner ERPOP [Member]	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ERPOP [Member]	DISTRIBUTIONS [Member] ERPOP [Member]	PARTIALLY OWNED PROPERTIES [Member] ERPOP [Member]
Balance, beginning of year at Dec. 31, 2020			$ 37,280	$ 10,532,037	$ 233,162	$ (43,666)
Balance, beginning of year at Dec. 31, 2020								$ 4,673
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				68,257	(68,257)
Exercise of EQR share options				68,807
EQR's Employee Share Purchase Plan (ESPP)				3,455
EQR restricted shares				6,572
EQR share options				2,541
EQR ESPP discount				798
Net income available to Units - General Partner		$ 803,558		803,558
OP Units General Partner distributions				(676,158)
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				(1,335)
Change in market value of Redeemable Limited Partners				(119,237)
Adjustment for Limited Partners ownership in Operating Partnership				(27,085)	27,085
Equity compensation associated with Units - Limited Partners					14,173
Net income available to Units - Limited Partners		27,903			27,903
Units - Limited Partners distributions					(23,366)
Change in carrying value of Redeemable Limited Partners					(1,745)
Losses reclassified into earnings from other comprehensive income	$ (7,000)	(7,000)				7,000
Distributions declared per Unit outstanding							$ 1.8075
Net income attributable to Noncontrolling Interests	835,736	835,736						1,957
Distributions to Noncontrolling Interests								(4,492)
Balance, end of period at Sep. 30, 2021			37,280	10,661,943	208,955	(36,666)
Balance, end of period at Sep. 30, 2021								2,138
Balance, beginning of year at Jun. 30, 2021			37,280	10,435,740	205,691	(39,029)
Balance, beginning of year at Jun. 30, 2021								2,365
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				1,597	(1,597)
Exercise of EQR share options				29,184
EQR's Employee Share Purchase Plan (ESPP)				788
EQR restricted shares				1,758
EQR share options				565
EQR ESPP discount				165
Net income available to Units - General Partner		431,178		431,178
OP Units General Partner distributions				(225,938)
Offering costs				(267)
Supplemental Executive Retirement Plan (SERP)				722
Change in market value of Redeemable Limited Partners				(17,271)
Adjustment for Limited Partners ownership in Operating Partnership				3,722	(3,722)
Equity compensation associated with Units - Limited Partners					3,642
Net income available to Units - Limited Partners		14,847			14,847
Units - Limited Partners distributions					(7,367)
Change in carrying value of Redeemable Limited Partners					(2,539)
Losses reclassified into earnings from other comprehensive income	(2,363)	(2,363)				2,363
Distributions declared per Unit outstanding							0.6025
Net income attributable to Noncontrolling Interests	447,332	447,332						534
Distributions to Noncontrolling Interests								(761)
Balance, end of period at Sep. 30, 2021			37,280	10,661,943	208,955	(36,666)
Balance, end of period at Sep. 30, 2021								2,138
Balance, beginning of year at Dec. 31, 2021			37,280	10,951,940	214,094	(34,272)
Balance, beginning of year at Dec. 31, 2021								18,166
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				1,680	(1,680)
Exercise of EQR share options				21,021
EQR's Employee Share Purchase Plan (ESPP)				3,280
EQR restricted shares				9,526	1
EQR share options				1,856
EQR ESPP discount				637
Net income available to Units - General Partner		615,573		615,573
OP Units General Partner distributions				(705,529)
Offering costs				(739)
Supplemental Executive Retirement Plan (SERP)				(269)
Acquisition of Noncontrolling Interests – Partially Owned Properties				(27,383)				(4,795)
Change in market value of Redeemable Limited Partners				127,570
Adjustment for Limited Partners ownership in Operating Partnership				9,156	(9,156)
Equity compensation associated with Units - Limited Partners					16,502
Net income available to Units - Limited Partners		21,024			21,024
Units - Limited Partners distributions					(23,078)
Change in carrying value of Redeemable Limited Partners					870
Unrealized holding gains (losses) arising during the period	23,413	23,413				23,413
Losses reclassified into earnings from other comprehensive income	(9,987)	(9,987)				9,987
Distributions declared per Unit outstanding							1.875
Net income attributable to Noncontrolling Interests	641,641	641,641						2,726
Contributions by Noncontrolling Interests								603
Distributions to Noncontrolling Interests								(18,267)
Balance, end of period at Sep. 30, 2022			37,280	11,008,319	218,577	(872)
Balance, end of period at Sep. 30, 2022								(1,567)
Balance, beginning of year at Jun. 30, 2022			37,280	10,883,459	216,326	(30,650)
Balance, beginning of year at Jun. 30, 2022								(1,734)
Conversion of OP Units held by Limited Partners into OP Units held by General Partner				196	(196)
Exercise of EQR share options				2,093
EQR's Employee Share Purchase Plan (ESPP)				902
EQR restricted shares				2,165
EQR share options				466
EQR ESPP discount				217
Net income available to Units - General Partner		322,252		322,252
OP Units General Partner distributions				(235,105)
Offering costs				(252)
Acquisition of Noncontrolling Interests – Partially Owned Properties				(28)				28
Change in market value of Redeemable Limited Partners				29,430
Adjustment for Limited Partners ownership in Operating Partnership				2,524	(2,524)
Equity compensation associated with Units - Limited Partners					3,343
Net income available to Units - Limited Partners		10,997			10,997
Units - Limited Partners distributions					(7,590)
Change in carrying value of Redeemable Limited Partners					(1,779)
Unrealized holding gains (losses) arising during the period	24,672	24,672				24,672
Losses reclassified into earnings from other comprehensive income	(5,106)	(5,106)				5,106
Distributions declared per Unit outstanding							$ 0.625
Net income attributable to Noncontrolling Interests	$ 335,165	$ 335,165						1,143
Distributions to Noncontrolling Interests								(1,004)
Balance, end of period at Sep. 30, 2022			$ 37,280	$ 11,008,319	$ 218,577	$ (872)
Balance, end of period at Sep. 30, 2022								$ (1,567)